For the last few weeks, I have experienced a sewer smell from one bathroom. I cannot locate the source. Up to this point I have taken the following steps...-Replaced the wax seal on the toilet-Poured bleach down the sink, tub and overflow openings on both, as well as in the toilet and the toilet inflow(?) tube-Snaked the vent from the roof down 25 feet (the house is only two stories Plus roof-Checked the Utrap on the tub from the basement to make sure it wasn't leaking-Checked the Utrap on the sink as well

I am really at a loss on what to do next. Any suggestions will be greatly appreciated.

I am not opposed to getting a professional to come in, but I wouldn't even know what to ask them to do at this point.